Clearance valve for compressors



Nrrao STATE WILLIAM PRELLWI'IYZ, OF EASTON, PENNSYLVANIA, ASSIGNOR TO INGERSOLIrRAND COMPANY, OF JERSEY CITY, NEW JERSEY, A CORPORATION OF NEW JERSEY.

CLEARANCE' VALVE FOR OOMPRESSORS.

' To all whom. it may concern.'

valves.

Be it known that I, WILLIAM PRELLWITZ, a citizen of the United States, a resident of EastonNorthampton C0unty,.and State 'of Pennsylvania, have invented a certain Clear-- ance Valve for Compressors, of which the .following is a speciication accompanied by drawin s. This invention relates to Huid compressors, but more particularly to a clearance valve for controlling the passage of fluid to' clearance pockets provided at either end of the compressor cylinder, in order to regulate the load of a compressor at constant speed.

The clearance valve forming the subject matter of this invention is adapted especially for a regulating system for compressors, such as disclosed in my U. S. Patent No. 1,027 ,7 60, granted May 28, 1912, in which patent Figure 2@ illustrates a clearance valve upon which my present invention is in some respects an o. improvement.

. Like the clearance valve of my priorl patent, my present clearance valve is 'ofthe poppet type, as I have found that such type of valve is preferable and is tighter than a piston valve for instance. My present objects a`re to produce avalve which is located' substantially entirely within the walls of the compressor in the clearance pockets, and yet is not erratic in action and will not slam in and out at intervals. The tendency to erratic action and slamming are disadvantages which it is highly desirable, if not impera; tive, to overcome and my improvement has overcome these difficulties in a clearance valve of the poppet type.

The invention is shown in one of its preferred forms in the accompanying drawings, in whichi Figure 1 isa transverse sectional elevation of a two stage compressor on the line 1-1 of Figure 2, fitted with my improved clearance valves. Y Y

. Figure 2, is a horizontal sectional plan view on the line2-2 of Figure 1, and

Figure 3 is an enlarged detail longitudinal sectional view taken through one of the Referring to the drawings, andA at first more particularly to Figures 1 and 2, a two stage compressor is shown for the purposes of illustration, having the -low pressure cylinderA, the li h lpressure cylinder` B and the intercooler` ir entersat the intake D Specircatiio'n of Letters Patent.

Patented July 11, 11922.

. and is discharged through the discharge pipe cylinders are furthermore provided with the usual inlet valves T and discharge valves U of any suitable type, in this instance plate valves being shown.

In accordance .with my improved clearance valve construction cylindrical valve guides V extend inwardly into the clearance pockets from the opening y R in the outer walls O of the cylinders. In this instance, the valve guides V are shown separate from the cyliners, but they might be cast as a part of the cylinders. Each guide V is provided with a barrel W having a bore X of smaller diameter, and a head Y having a bore Z of larger diameter. The -valve guides V may be threaded into the openings Rin the outer walls of the cylinders, as by means of the screw threads a as shown, or otherwisesecured in position. A suitable cover b is pro-A vided for the 4outer end of each valve guide, suitably secured thereto as by means of the screws c and suitable means are provided for admitting pressure from an external source to t-he head of each valve guide, for thisfpurpose an opening being provided in each cover b. These openings may be connected by piping d to a suitable regulator (not shown) which admits receiver pressure tothe valve guides to operate the clearance valves ance valve is preferably providedwith circumferential lubrication grooves k while the enlarged head g of the valve is preferably provided with piston rings o.

In the operation of the device, the larger -outer pressure'area of a clearance valve f is `p of the valve and this variable pressure changes with the stroke of the compressor tending to open the valve. By this means, the passage of fluid from the cylinder to the di'erent clearance pockets is controlled in accordance with the load of the compressor ,at constant compressor speed.

I have found that clearance valves constructed in accordance with this invention operate satisfactorily and well, and are not erratic .in action. 0n the contrary, they act evenly and consistently and do not slam in and out at intervals. Other advantages reside in the fact that the valves will'easily and readily centerv upon their seats andare maintained in alignment by means of valve guides. The space g within. the head of a valve guide and between vthe guide and the'head of the valve, is substantially under the pressure in a clearance pocket, 1 since there -is sufficient clearance provided between the barrel of the guide and the body portion of the valve and without piston rings to prevent' excess pressure in the space g.-

I claim:

1. In a compressor, a compressor cylinder formed with inner and outer walls having a clearance pocket between them and aligned openings in the. walls, a cylindrical valve guide extending inwardly from the opening in the outer wall, said guide having a differential-bore and a cover for its outer end, means for admitting pressure from an external source to the outer end of said-giiide, a

cylindrical dierential clearance valve of the poppet type movable -wlthin said guide and adapted to cooperate with'a'seat at 'the said lopening the inner wall of thelcylinder, the

larger outer pressure area of the valve being subject to said external pressure tending to t'he passage of fluid from the cylinder to the i clearance pocket is controlled in accordance with the load of the compressor at substanp ,tially constant compressor speed.

I 2. In a compressor, a compressor cylinder formedv with inner and outer walls having a clearance pocket between them and aligned openings in the wallsfa cylindrical valve 'guide extending inwardly from" the'opening in the outer wall provided witha barrel having a bore of smaller diameter and a head having a bore of larger diameter, a cover for ,the valve guide, means. for admitting pressure from an external source to the head of said valve guide, a, cylindrical differential clearance valve of the poppet type having'an enlarged head within the head of the guide and a smaller body portion extending through ,the guide barrel and adapted to seat at the said opening at the innerv wall of the cylinder, the larger outer pressure area of the valve being subject to said external pressure tending to maintain the valve -clo'sed against varlable pressure upon. the :smaller inner pressure area changing with'the stroke of the compressor tending to open the valve, whereby the passage of ud from the cylin` der to the clearance pocket is controlled :inl

accordance with the load of the compressor at substantially constant compressor speed.

In .testimony whereof. I have signed this specification.

t WILLIAM PRELLwITzQ 

